I. Field of the Invention
The present invention relates generally to energy transfer units where such units include internal combustion engines, pumps, compressors, and the like. More particularly, the present invention relates to an energy transfer unit comprising an upper wall, a lower wall spaced apart from the upper wall and being substantially parallel thereto, and at least three piston members pivotably mounted between the upper wall and the lower wall forming an alternatingly expanding or contracting compression chamber therebetween.
II. Description of the Prior Art
Improvements of energy transfer units including compressors, pumps and internal combustion engines are continually being sought. Ever since early experiments in the use of conventional internal combustion engines began in 1861 with the Otto engine, improvements in the manufacture and construction of such engines have been sought. For reasons obvious, a good internal combustion engine construction including pistons, valving and the like also translates into a good compressor and a good vacuum pump. Accordingly, if one improves one type of energy transfer unit, one improves all types.
Several approaches have been taken toward improving the efficiency of energy transfer units. Such advancements are well known as the four-stroke and the two-stroke engine. Other modifications include the rotary-valve engine, the two-port poppet-valve engine, and the reed-valve engine. These modifications were directed to improving valving, and to some extent have proven valuable.
However, despite all of these improvements to valving, piston construction has essentially remained the same. Pistons, as they are elongated cylinders having a face at one end and a connecting shaft at the other end, have been modified by including hemispherical piston faces and the like. A more or less radical modification of the piston engine was revealed by construction of the Stirling engine.
An even more radical modification of the piston engine may be seen in rotary engines. Such modifications include rotary engines with elliptical pistons, and rotary engines having eccentric pistons. Also known are rotary engines having concentric pistons.
The most recent and well known modification of a piston is disclosed in the Wankel engine. This engine includes a rotor in place of the conventional or modified piston. The rotor is more or less triangularly-shaped and represents the form called a trochoid. This triangular construction has slightly rounded sides, and each of its three faces includes a recess or pocket defined therein to form a combustion chamber.
However, the Wankel engine has not proved the panacea that it was hoped to be. For a variety of reasons mostly due to failed seals and the like, the Wankel never proved as commercially popular as anticipated.
Perhaps the greatest disadvantage the Wankel and other radical piston shapes have suffered from is the fact that within one compression chamber there is typically provided only one piston. Accordingly, in this construction, expansion can take place only in one direction by the movement of only one wall of the chamber.
For some time automotive engineers have known that the most efficient shape for a combustion chamber or a compression chamber was spherical. However, spherical chambers are, for all intents and purposes, impossible to create, thus automotive engineers have stopped short of improving on conventional and even more or less radical piston forms.
Accordingly, the prior approach is to solving the problem of maximizing energy transfer unit efficiency have failed and today we are still in a position where we use only a conventionally-styled piston element.